Insecticidal oil compositions



Patented Get. 25, 1938 msao'riomai. on,

m Hunter Volck, Watson, Calif assignor to California ration, aware NoBra 1:

Spray-Ghemicai Goa-pokeley, Calif., a corporation of Del- Thepresent'invention relates to new and improved insecticidal oilcompositions and more particularly to insecticidal oil compositionswhich are easily dispersed in water by mechanical agitation and V whichare therefore especially adapted to the so-called tank-mix orin-the-field method of preparing insecticidal oil emulsion sprays and toa method of producing the same. This invention is a continuation inpartof the disclosure in my copending application, Serial Number 733,251,filed June 30, 1934, now issued as United States Patent No. 2,109,095.

Numerous so-called "soluble or miscible" oils have in the past beenprepared for various uses among which is their use in insect controlwork. Such oils have possessed the common property of spontaneousdispersion on contact with water or at least of being readily dispersedwhen vigorously. agitated with water. Oils so prepared for insecticidaluse have thus been selfemulsifying to the extent that they might havebeen, and sometimes were, employed as tank-mix oils for the-preparationof insecticidal sprays at the point of actual application.

It is a fact, however, that the oil-soluble materials which have' beenemployed as internal emulsifiers in the preparation of soluble oils haveusually been of such character as to make harmful to growing vegetationwhen the emulsifiers have been used in quantity sufficient to render theoil self;emulsifying to a useful degree.

Use of the well known soluble oils in insecticidal oil-solubleemulsifiers which had been previous- 45 to the oil in insuficientdegree, they were too critical in operation or they were uneconomical.

It is the broad object of this invention to provide an insecticidal oilcomposition for tank-mix spray preparation which shall have none of theforegoing defects and which shall have certain functions, desirable ininsecticidal oil sprays, in addition to ready dispersibility.

I have discovered that certain of the oil-solueven the most phytonomicoils destructively ly used they have generally failed of widespreadutilization because they imparted emulsifiability Application go: 13;1935,

ble alkali sulfonates re'sulting'from the i i J or treatment ofpetroleum distillates or extracts therefrom may, when properly purifiedand neutralized, be used in relatively small. amounts as internalemulsifiers in insecticidal petroleum 5 oils for the preparation ofdormant or wintersprays and in still smaller amounts, in combinationwithsubstances which may be referred to as interfacial tension modifiers, inthe production of readily emulsible insecticidal oils applicability andvery great utility. j

While some attempts have hitherto been made to utilize oil-solublepetroleum sulfonates in the preparation of self-emulsifying oils forinsecticidal use such attempts have, so far as I am 1 6 aware, met'withlittle if any commercial success. When used alone such sulfonates arerequired in amounts of 20%to 40% by weight relative to the oil in orderto render a phytonomic oil. self-emulsifying. Such high percentages are,as 20 might be expected, decidedly harmful to growing vegetation andtherefore could be used only in sprays for application to dormantvegetation and even then only with considerable risk of causing seriousdamage. So far as the literature 25 on the subject discloses and so faras my experience goes, oil solutions of materially lesser amounts ofpetroleum sulfonates have-hitherto found no utility in the absence ofwater-soluble emulsifiers adequate in themselves to effect soemulsification.

in carrying out my invention I employ the oilsoluble sulfonates producedfrom petroleum distillates in the boiling range of heavy kerosenes,mineral seal oils,-or light to medium lubricating oils, 1. e., oils ofmolecular weight from about 200 to 400 or above. These sulfonates asproduced or usually after careful neutralization are dissolved in thedesired phytonomic oil in relatively smalLproportions, always less than10% 40 and usually less than 1% by weight. For the preparation of ageneral utility composition for summer spraywork from 0.4% to about 0.8%will, when used as hereinafter directed, be found to give good results.For winter or dormant sprays from 3% to about 10% may be used ifdesired.

Oils containing very low percentagesof sulfonates for instance belowabout 3%"by weight have been found to be substantially harmless togrowing vegetation when the oil is applied with -99 partsof water. Assuch they are, however, not self-emulsifying to any useful degree and itis at this point that the present invention had its beginning.

It was first found that certain simple organic so of wide 10 liquidswhich are both oil-soluble and watersoluble to a considerable degree areparticularly usefulin rendering oils containing very low concentrationsof alkali petroleum sulfonates easily dispersible in water whichcontains no additional emulsifier of any sort. Certain lowmolecular'weight ketones, alcohols, aldehydes, esters, ethers, amines,amides and the like having an appropriate coeflicient of distributionbetween 011 and water are effective in this respect. From this group theindividual compound which was found to combine the highest degree ofefllcacy and economy with the most ready availability was dimethylketone: ordinary acetone. I

The quantity of such third ingredient which it was found necessary touse in order to secure ready mechanical dispersibility of oilscontaininga few tenths of one percent of petroleum sulfonates resulting inadequately stable emulsions for tank-mix spray preparation was ingeneral surprisingly small. In the case of acetone, 0.25% by volume onthe basis of the oil used produced a marked effect and 1.0% producedready dispersibility adequate for any tank-mix operation though so farashas yet been found, larger amounts may be employed, if desired, withoutharmful effect.

It was next found that by employing as the interfacial tension modifierin such compositions certain substances the molecules of which are ingeneral somewhat more complex, other desirable characteristics in.addition to ready mechanical dispersibility may be imparted to oils foruse in tank-mix spray preparation. Two character istics in particular,which have for some time been recognized as desirable in any oilemulsion or dispersion spray for insecticidal use may be readilyrealized by the proper choice of such modifying agents.

As has often in the past been pointed out, theleaves and fruit which itis most often desired to treat for insect control as well as mostinsects themselves are more readily wetted by 011 than by waterandhe'nce to secure worth while results through the application of adispersion of oil-inwater the function of oil-wetting must be present toa considerable degree. To this end various Spreaders have beenincorporated in the standard insecticidal oil emulsions of commercewhile the emulsions have further been rendered quickbreaking" as faraspossible consistent with the conditions of storage and handling. Bothsuch expedients have to a certain degree been carried over into thefield of tank-mix operation, but

even at best such dispersions have seldom been satisfactorilyoil-wetting.

I have now found, however, that 'certain of the substances which I havetested as interfacial tension modifiers for use in oils containing thevary small percentages of alkali petroleum sulfonates hereinabovedisclosed are capable of imparting the characteristicof oil-wettingtotankmix sprays prepared from such compositions and, carrying thecustomary l-4% of oil, to a remarkable and highly satisfactory degree. Ihave further observed that mechanical dispersions of such oilcompositions, even when prepared by mild shaking of the usualproportions of oil and water in a closed flask or bottle, invariablyform a certain proportion of invert (water-in-oil) emulsion and it isapparently to this new phase. which is inherently oil-wetting, that thesuperior oil-wetting characteristics realized in my new tank-mix spraysis to be attributed.

The second desirable characteristic of oil dispersion sprays which Ihave found to be realizable throughproper choice of materials, to beused as interfacial tension agents, is somewhat more diflicult either toevaluate or to explain but is none the less real and is much prized bythe practical spray operator.

The usual fine, stable, dilute, emulsions prewere foundwhich gave notonly 'eas'y dispersibility and superior oil-wetting as hereinabovedescribed but in addition imparted liveness or frothiness to thedispersion in very marked degree.

The over-all result of these several discoveries is therefore that bydissolving a relatively very.

small 'quantity of petroleum sulfonic salt and an equally small or evensmaller amount of another material, selected as hereinafter disclosed,in any desired insecticidal petroleum oil a composition results fromwhich insecticidal sprays with a novel and highly desirable combinationof characteristics may be produced by the now widely used tank-mixmethod.

While a considerable number-of materials have been tested in thecapacity of interfacial tensionmodifiers for this use only the broadestof generalizations are yet possible as to the molecular structure orconfiguration which is responsible for each of the characteristics justenumerated.

In general the simple, low molecular weight, aliphatic alcohols,aldehydes, ketones, etc., of appropriate oil-water solubility appear toinfluence primarily ease of dispersion while certain substancescontaining an aromatic or hydroaromatic nucleus with one or more polargroups and one or more aliphatic groups attached are able in addition tocontribute frothing and/or oil-wetting apparently depending upon thenumber,- position and identity of the groups attached to or closelysurrounding the ring.

Aromatic nuclei having from ,one to four carbon atoms in side chains andan'KOH) radical as the polar group appear more likely to con-.

tribute both oil-wetting and frothing to a desir-' able degree thanother combinations which have been tried. Where the (0H) radical is inthe single side chain as in benzyl alcohol the frothing effectpredominates while when no aliphatic substituent is present and in itsstead a second aromatic nucleus is attached to the ring carrying the(OH) group as in p-naphtholor p-hydroxy diphenyl invert emulsionformation and oil ting is the predominating eflect.

The following table includes a number of compounds which have been foundto possess particularly' interesting characteristics in this connection.While results are given only inqualitative terms they serve to indicatethe relation of activity to molecular structure. The tests wereperformed in the laboratory as follows: 1% by volume of neutralizedpetroleum sulfonate was dissolved in a medium phytonomic oil and thenmodifier to the extent indicated in the table was wet- addw. For partsof the resulting mixture and ainew-six parts of tap.'water were thenhand shaken in a stop'pered bottle and the observations taken. The checksample contained sulfonate but no modifier.

Table of results Concontrs- Easyofdis- Liveemnl- Oil-globules IndiaModifier tlon persiou Invert sion stick to glass ggfg Nnnn No Poor(tenacious) No.'. Yes No.

Acetone y r. Yes- N Yes- Fair. Do 1 o Very No--- Yes Yes. fi-nephthol0.l%(sat'd.) Yes. Yes Yes No Yes. .lhymol 1' Yes. Yw. Fair N Yes.Orcinol Saturated.-. Yes No Yes Fair. Menthol- 17 Yes. Very No Yes.p-Cmsnl 34 Yes. Y s N Yes. 8.1).fiineoil 1% Fair Yes-. No Yes. fl-mtifiithyl-r'nethyl 111- Fair Yes. No Yes 0 er. Benzylalcohoi 2% Little VeryFenchylalcohol 1% Yes es. p-0H-diphenyl. Saturated Much (tenacious)-Fair 4-OH-l-3-Me-ben- 1% Yes. Fair zene. p-NOg-toluene 1% YesDi-o-toiyl-thiourea- Saturated Poor (tenacious) a-Naphthyiamine Fair VMethyl crisis 1% Cresylicacid Yes Yes While the check oil, withoutmodifier, could be made to produce some invert emulsion neither the oilnor the invert, when formed, was sulficiently readily dispersible foruse as a tank-mix spray; This same lack of dispersibility on the part ofthe invert emulsion, referredto in.the

foregoing table of results as tenacity. wasalso experienced with severalof the modifiers tested. It is not surprising to find that modifierswhich imparted only fair dispersibility to the oil itself were likelyto-permit a tenacious, curd-like layer of invert to form and persisteven on vigorous shaking.

The fact as to whether, after shaking a given test sample as previouslydescribed, the oil was observed to adhere to the inside walls ofthebottle has been recorded in column seven of the foregoing table.Without attempting any'explanation ofwhy it should be so, it was foundthat only those compositions which did not permit the oil to stick tothe glass gave a live dispersion containing easily dispersible invertemulsion and a desirable degree of as a whole.

The delicacy of the dispersion systems with which we are her dealing israther forcefully indicated by the fact that one-half percent of purep-cresol is inferior as a modifier to onefifth percent of commercialcresylic acid. When such diiferences-in effectiveness are found to existbetween a pure compound and a mixture of its isomers it should not besurprising. to find very considerable differences betweendifferent'compounds whose molecules are apparently very slim" ilar. Ingeneral, however, closely similar molecules appear to give results whichare hard to distinguish, one from the other, by purelyqualitative tests.lifhis is substantiated by the results obtained with the four substancesthymol, 'menthol, fenchyl alcohol and terpineol (the major constituentof steam distilled pine oil)" which, while they contain the six memberedcarbocyclic ring structure common to all substances shown by theforegoing table to give the desired combination of effects, difier aswidely among themselves in the specific nature of that ring structure asany materials studied and yet, having identical or closely similarattached aliphatic carbon and oil-wetting by the spray sprays isappraised without regard to the comfact. The combination of cresylicacid and pine oilis a good example. Other combinations suchas acetone orbenzyl alcoholwith p-hydroxy diphenyl or p-naphthol are worthy ofmention. l'he following examples of readily dispersible .oils fortank-mix insecticidal spray preparation are typical of my preferredcompositions:

Example 1 I Percent Q Insecticidal mineral oil (medium) 99.0

' Neutralized petroleum sulfonates -0.8 cl'sylic acid 0.2

. Example 2 Insecticidal mineral oil (medium) 90.0 I Neutralizedpetroleum 'sulfonates 1.0 Steam distilled pirie oil 1.0

Example 3 Mineral oil 99.0 Sulfonates 0.9 p-,naphthol 0.1

100.0 Example 4 Mineral oil 98.6 Sulfonates 0.8 Cresylic' acid. .1 Pineoil .5 100.0

Example Mineral oil 98.6

Sulfonates 0.8

p-naphthol -a 0.1.

Benzyl alcohol 0.5

One of the outstanding features of my invention resides in thesurprisingly small amounts of additional agents which I have discovered.to he amply sufiicient in a phytonomic oil to give highly satisfactorytank-mix sprays. While this is of course important in keeping down thecost of materials it is vastly more important in that the phytonomiccharacter of the oil itself is changed but very little if at all.

The contrast in this respect of the foregoing examples with the onlyhitherto known readily dispersible oils which employed suifonates (20-40%) is extremely significant.

While, as previously mentioned, up to about 3% I of sulfonates may ifdesired be employed in oils for application as aqueous dispersions togrowing vegetation without considerable phytocidal effect- I have foundin practice that little if any advantage is to be gained by using morethan 1.0%. In fact, in some instances, I have actually found that abetter deposit of oil is left on the sprayed host when sulfonate is usedat 1.0% than when at 3.0%.

Another outstanding feature of my invention resides in the degree ofoil-.-Wetting which is obtained. lihis I have hereinbefore suggested aspossibly being due to the fact that a certain proportion of oil isthrown by my preferred compositions into a water-in-oil, invert,emulsion. Just what portion of the oil should go into the conventionaloil-in-water emulsion and what portion into water-in-oil emulsion forbest over-all results has not yet been determined and probably would beextremely difficult to determine with accuracy. As'a very rough estimateit appears that from about to as much as 50% or more of the .oil shouldbe in the invert phase.

Still another very important feature of my-invention arises from thefact that the operation of my compositions not only is not interferedwith when hard water is employed, as is the case with many hithertoemployed insecticidal mineral oil compositions, but actually requiresthat the water possess at least a moderate degree of hardness for bestresults. Where water of very low hardness is encountered I have found abetter oil deposit to result with less absorption by, the plant tissueswhen hard-wall plaster (calcium sulfate), calcium chloride or anequivalent hardness producer is added to the water before the oilcomposition is dispersed. I prefer hard-wall plaster, because of itsready availability, and add it at the rate of A to /2 pound per 100gallons of water.

The oil-soluble petroleum sulfonates as marketed are usually in solutionin oil and very often contain an appreciable excess of alkali. This maybest be neutralized with an oil soluble organic acid such as glacialacetic whereupon the liberated alkali acetate slowly settles out and maybe removed by filtration or decantation.

As will readily be understood by those skilled in the art, no particularkind or quality of oil is essentialto the operation of my invention, theoil for any particular composition being chosen entirely on its ownmerits and with regard to the speciflc'use to which it is to be put.

As'wiil be appreciated from the nature of the solution in the oil andconsists of less relative to oil compositions herein described and thetankmix method of operation for which they are par-- ticularly designedthey are emulsible" in the sense that they are emulsified on meremechanical mixing in water or an aqueous solution containing noemulsifier whatever and such is the construction to be given that termin the appendedclaims.

Having now described my invention which consists essentially in thecombination of certain classes of materials in solution in aninsecticidal oil and in the novel dispersions produced therewith andhaving taught how it may be employed 'th substantially improved results,what I claim is:

I claim:

1. An emulsible insecticidal oil composition the emulsifying componentof which is in solution in the oil and consists of less than 10%,relative to the oil, of petroleum sulfonic salts and an organic,oil-watefinterfacial tension depressant the molecules of which contain anonpolar, oilsoluble, hydrocarbon part comprising a six-meme beredcarbocyclic ring and a water-soluble part comprisinga metal-free'polargroup attached to said ring.

2. An emulsible insecticidaloil composition the emulsifying component ofwhich is in solution in the oil and consists of less than 10%, relativeto the oil, of an alkali salt of petroleum sulfonic acids and anorganic, oil-water, interracial tension.depressant the molecules ofwhich contain a nonpolar, oil-soluble, hydrocarbon part comprising asix-membered carbocyclic ring to which is attached from one to fouraliphatic carbon atoms and a polar water-soluble part comprising a metalfree oxygen containing group.

3. A phytonomic emulsible insecticidal oil composition the emulsifyingcomponent of which is in solution in the oil and consists of less than3%, relative to the oil, of petroleum sulfonic salts and less than about2%, relative to the oil, of an organic, oil-water interfacial tensiondepressant the molecules of which contain a nonpolar, oilsoluble,hydrocarbon part comprising a six-membered carbocyclic ring and awater-soluble part comprising a metal free polar group attached to saidring.

4. A phytonomic emulsible insecticidal oil composition the emulsifyingcomponent of which is in than 3% relative to the oil, of an alkali saltof petroleum sulfonic acids and less than about 2%, relative to the oil,of an organic, oil-water, inter-facial tension depressant the moleculesof which contain a.

nonpolar, oil-soluble, hydrocarbon part comprising a six-memberedcarbocyclic ring to which is attached from one to four aliphatic carbonatoms and apolar water-soluble part comprising a metal free oxygencontaining group.

5. A phytonomic emulsible insecticidal oil composition-the emulsifyingcomponent of which is in solution in the oil and consists of less than3%, the oil, of an alkali salt of petroleum sulfonic acids and less thanabout 2%, relative to the oil, of an'organic, oil-water, interfaciaitension depressant the molecules of which contain a nonpolar,oil-soluble, hydrocarbon part comprising a six-membered carbocyclic ringto which is attached from one to four aliphatic carbonatoms and a polarwater-soluble part comprising an hydroxyl group.

6. A phytonomic emulsible insecticidal oil composition the emulsifyingcomponent of which is in solution in the oil and consists of less than3%,

relative to the oil, of petroleum sulfonic salts and less than about 2%,relative to the oil, of an organic, oil-water interfacial tensiondepressant containing a six membered carbocyclic ring and a polar groupand which is selected from the group consisting of cresylic acid, steamdistilled pine oil, p-naphthol, thymol, menthol, ,B-naphthyl-methylether, fenchyl alcohol, p-hydroxy diphenyl, ben'zyl alcohol, xylenol andorcinol.

7. An emulsion spray for insecticidal use comprising the composition ofclaim 1 and water,

said spray having a substantialproportion of the contained oil in awater-in-oil dispersion dispersed in the aqueous continuous phase.

8. An emulsion spray for insecticidal use which comprises thecomposition of claim 1 dispersed in a hard water.

9. An emulsion spray for insecticidal use which comprises thecomposition of claim 6 dispersed in a hard water.

WILLIAM HUNTER VOLCK.

